Prestabilization of halogen-containing polymers

ABSTRACT

The invention relates to a process for preparing a stabilized suspen-sion/emulsion polymer of halogen-containing monomers with addition of a polymer stabilizer mixture compatible with the polymerization medium prior to, during or directly after the polymerization process, and to the polymers pre-pared by this process.

[0001] The invention relates to a process for preparing a stabilizedsuspension/emulsion polymer of halogen-containing monomers with additionof a polymer stabilizer mixture compatible with the polymerizationmedium prior to, during or directly after the polymerization process,and to the polymers prepared by this process.

[0002] Suspension or emulsion homopolymers and copolymers ofhalogen-containing monomers have limited thermal stability which has tobe optimized by adding various stabilizer systems or combinations ofthese so that the materials can be processed to give industrially usefulfinal products.

[0003] PVC polymerization may be taken here as an example of thepolymerization of halogen-containing polymers. In PVC polymerization,the polymer is mostly prepared in aqueous systems in the form ofsuspension, microsuspension or emulsion PVC. In this process, themonomer(s) is/are added to the aqueous polymerization medium composed ofa mixture of polymerization catalyst (initiator), dispersion systems,agents to prevent adhesion, (protective) colloids or dispersants, andthe polymerization is carried out. Once the reaction has ended, thepolymer formed is processed by spray drying to give polymer powder or isisolated by filtration, centrifuging, or similar separation steps, andwhere appropriate washed and finally dried at elevated temperatures.

[0004] The drying generally leads to the first thermal stress placed onthe polymer and should therefore in principle be carried out very gentlyin order to prevent thermal degradation and associated discoloration ofthe vinyl polymer.

[0005] The drying gives a white or near-white fine powder which can thenbe treated with other additives, processing aids, and also heat or lightstabilizers and can be processed with heat in the melt or on rolls or inkneaders, extruders, or other equipment, to give the desired finalproducts (mouldings, etc.).

[0006] The optimized polymer mixture for the particular application canonly be made available by adding additives, modifiers and/or otherstabilizers of varying type.

[0007] Until now the polymer has always been stabilized only after itsisolation from the aqueous reaction medium of the polymerizationreactor, since there have been no available stabilizers which arecompatible with the polymerization medium or soluble therein. Apolymerization medium based on water is usually used. The stabilizersystems used hitherto are not only incompatible or insoluble in thepolymerization medium but are also incompatible or insufficientlycompatible with the polymerization process. This means that they canlead to coagulation (breaking of the polymer dispersion) or even inhibitthe polymerization and thus lead to yield losses or worse. Attempts tostabilize the polymer dispersion have therefore hitherto beenunsuccessful.

[0008] JP 61-009451 indicates a stabilizer system specifically for PVC,composed of a combination of ethanolamine and perchloric acid. Thisinvolves perchlorate salts with ammonium salt structure, and these canbe obtained by adding primary, secondary or tertiary ethanolamines to aperchloric acid solution.

[0009] Ammonium perchlorate salts are generally compounds which aresensitive to heat and shock and therefore are accompanied by a certainrisk of explosion, making them unsuitable for large-scale industrialapplications in plastics processing. This combination is used only afterpolymerization has ended, since the components have an adverse effect onthe polymerization procedure. The molar ratios in which the componentshave to be used also severely restrict the ideal range of use of thestabilizer combination.

[0010] EP 0 281 210 describes a stabilizer system composed of ahomogenized suspension of an antioxidant which is insoluble in thepolymerization mixture and has to be added to the modifiedpolymerization mixture towards the end of the polymerization of vinylchloride, but is not effective against the known ionic thermaldegradation of PVC.

[0011] U.S. Pat. No. 4,252,705 discloses stabilizer systems for PVC, butthese are based on insoluble N,N′-diphenylurea and severely restrict thescope of application of the resultant PVC.

[0012] Other additives usually used for post-stabilization of finishedPVC powders cannot be used because of incompatibility or hydrolyticdecomposition.

[0013] For example, the halogen-containing polymer PVC can be stabilizedby a number of additives. Compounds of the heavy metals lead, barium andcadmium are particularly well suited to this purpose, but are nowadayssubject to criticism on environmental grounds or due to their heavymetal content; other stabilization systems based on Ca/Zn or tin orbased on organic materials are also known, but for the reasons mentionedcannot be used for prestabilization (cf. “Kunststoffadditive” [Plasticsadditives], R. Gächter/H. Müller, Carl Hanser Verlag, 3rd edn. 1989,pages 303-311 (see also 4th edition of 2001) and “Kunststoff HandbuchPVC” [Plastics Handbook PVC], volume 2/1, W. Becker/D. Braun, CarlHanser Verlag, 2nd edn., 1985, pages 531-538; and also Kirk-Othmer:“Encyclopedia of Chemical Technology”, 4th ed. 1994, Vol. 12, HeatStabilizers, pp. 1071-1091).

[0014] It has now been found that the stabilization of thehalogen-containing polymer can take place while the polymerizationmedium is still present, prior to isolation of the polymer from itsmother liquor or prior to breakdown (breaking) of the polymerdispersion. For the purposes of this invention, the general termpolymerization medium encompasses dispersion systems, colloid systems,emulsion systems or suspension systems, i.e. various systems which canarise during polymerization of halogen-containing monomers. The termpolymerization of halogen-containing monomers also encompassescopolymerization of halogen-containing monomers with one or morenon-halogen-containing monomers or a mixture of these.

[0015] This means that, even though the reaction medium is mostlyaqueous, stabilization can take place prior to, during and after thepolymerization.

[0016] Surprisingly, this addition of substances foreign to thepolymerization has no adverse effect on the polymerization medium. Noris there any adverse effect on polymerization activity and polymeryield, and indeed in some cases the yields found are higher.

[0017] The invention therefore provides a process for preparing astabilized suspension/emulsion polymer of halogen-containing monomerswith addition of a polymer stabilizer mixture compatible with thepolymerization medium prior to, during or directly after thepolymerization process.

[0018] To this end, the stabilizer system is added to or dissolved inthe polymerization medium by the usual laboratory methods, directly inthe form of a solid or mixture of solids, or in the form of a solutionor dispersion in a suspension medium or, respectively, solventcompatible with the polymerization medium. The addition may take placeprior to, during, or after the polymerization. The dispersion medium isthen, where appropriate, separated off and the polymeric product isdried. Commonly used industrial methods such as filtration,centrifuging, or else preferably spray drying are used to remove thedispersion medium. This gives a very intimate mixture of the stabilizersystem with the polymer, and even during the required first drying ofthe polymer powder the stabilizer can begin to exert its stabilizingaction and thus prevent thermal degradation during the drying procedure.In addition, its incorporation into the polymer is more thorough than inthe processes which have been carried out hitherto and do not bring thestabilizer system into contact with the polymer until drying iscomplete. The result of this intimate contact of the stabilizer systemwith the polymer is substantially less initial thermal stress on thepolymer for incorporation of the stabilizer into the polymer network;indeed, this stress can be avoided completely, since thermal shaping cantake place directly without any further stabilization. Nevertheless, itis also possible for the identical additional stabilizing materials tobe added subsequently to the resultant polymer powders in the usualway—if necessary.

[0019] It has been found that stabilizer mixtures which are compatiblewith the polymerization medium, i.e. which are compatible with thedispersion/emulsion systems of the polymerization and with thepolymerization process, can be used in the process of the invention. Inparticular, these stabilizer systems may be systems which arewater-soluble and dispersion-compatible.

[0020] The present invention therefore provides a process for preparinga stabilized suspension/emulsion polymer of halogen-containing monomerswith addition of a polymer stabilizer mixture compatible with thepolymerization medium prior to, during or directly after thepolymerization process, characterized in that the polymer stabilizermixture encompasses at least

[0021] a) a perchlorate and/or

[0022] b) an alkanolamine of the formula (I)

[0023] where

[0024] x=1, 2 or 3;

[0025] y=1, 2, 3, 4, 5 or 6;

[0026] n=from 1 to 10;

[0027] R¹,R²=independently of one another H, C₁-C₂₂-alkyl, -[—(CHR³_(a))_(y)-CHR³ _(b)-O—]_(n)-H, -[—(CHR³ _(a))_(y)-CHR³ _(b-—O—])_(n)-CO—R⁴, C₂-C₂₀-alkenyl, C₂-C₁₈-acyl, C₄-C₈-cycloalkyl, where thismay have OH substitution in the β-position, C₆-C₁₀-aryl, C₇-C₁₀-alkarylor C₇-C₁₀-aralkyl, or, if x=1, R¹ and R² may also, together with the N,form a closed ring having from 4 to 10 members, composed of carbon atomsand, where appropriate, of up to 2 heteroatoms, or if x=2, R¹ may alsobe C₂-C₁₈-alkylene which, at both β-carbon atoms, may have OHsubstitution and/or have interruption by one or more O atoms and/or oneor more NR² groups, or be dihydroxy-substitutedtetrahydrodicyclopentadienylene, dihydroxy-substitutedethylcyclohexanylene, dihydroxy-substituted 4,4′-(bisphenol A dipropylether)ylene, isophoronylene, dimethylcyclohexanylene,dicyclohexylmethanylene or 3,3′-dimethyldicyclohexylmethanylene, and ifx=3, R¹ may also be trihydroxy-substituted (tri-N-propylisocyanurate)triyl;

[0028] R³ _(a) and R³ _(b)=independently of one another C₁-C₂₂-alkyl,C₂-C₆-alkenyl, C₆-C₁₀-aryl, H or CH₂—X—R⁵, where X═O, S, —O—CO—or—CO—O—;

[0029] R⁴═C₁-C₁₈-alkyl/alkenyl or phenyl; and

[0030] R⁵═H, C₁-C₂₂-alkyl, C₂-C₂₂-alkenyl or C₆-C₁₀-aryl, and/or

[0031] c) the salts of a) and b).

[0032] The invention also provides a process which uses stabilizermixtures compatible with and/or soluble in the polymerization medium,encompassing at least

[0033] a) a perchlorate salt and/or

[0034] b) a reaction product of a mono- or polyfunctional epoxide andammonia or, respectively, a mono- or polyfunctional dialkyl(aryl)- ormono-alkyl(aryl)amine and/or

[0035] c) the salts of a) and b).

[0036] Examples of the alkanolamines of the general formula (I) arecompounds where R¹ and R²=methyl, ethyl, propyl, butyl, cyclohexyl,octyl, lauryl, tetradecyl, hexadecyl, stearyl, oleyl, allyl, phenyl orbenzyl or hydroxyalkyl and R³═H, methyl, ethyl, propyl or butyl.Preference is given to alkanolamines where R¹=lauryl, tetradecyl,hexadecyl, stearyl, or oleyl, where R²=hydroxyalkyl. It is also possibleto use ethoxylates and propoxylates of triethanol- andtriisopropanolamine, and also of fatty amines of vegetable or animalorigin. Preference is given to trialkanolamines andmonoalkyl/alkenyldialkanolamines where R³═H or methyl and y=1, inparticular fatty amines which have been reacted twice with ethyleneoxide or with propylene oxide.

[0037] Other compounds with very good suitability can be found in thefollowing list.

[0038] Methyl- or dimethylamine reacted once or twice with ethyleneoxide or with propylene oxide.

[0039] Propyl- or dipropylamine reacted once or twice with ethyleneoxide or with propylene oxide.

[0040] Isopropyl- or diisopropylamine reacted once or twice withethylene oxide or with propylene oxide.

[0041] Butyl- or dibutylamine reacted once or twice with ethylene oxideor with propylene oxide.

[0042] Isobutyl- or diisobutylamine reacted once or twice with ethyleneoxide or with propylene oxide.

[0043] Pentyl- or dipentylamine reacted once or twice with ethyleneoxide or with propylene oxide.

[0044] Isopentyl- or diisopentylamine reacted once or twice withethylene oxide or with propylene oxide.

[0045] Hexyl- or dihexylamine reacted once or twice with ethylene oxideor with propylene oxide.

[0046] Isohexyl- or diisohexylamine reacted once or twice with ethyleneoxide or with propylene oxide.

[0047] Heptyl- or diheptylamine reacted once or twice with ethyleneoxide or with propylene oxide.

[0048] Isoheptyl- or diisoheptylamine reacted once or twice withethylene oxide or with propylene oxide.

[0049] Octyl- or dioctylamine reacted once or twice with ethylene oxideor with propylene oxide.

[0050] Isooctyl- or diisooctylamine reacted once or twice with ethyleneoxide or with propylene oxide.

[0051] Nonyl- or dinonylamine reacted once or twice with ethylene oxideor with propylene oxide.

[0052] Isononyl- or diisononylamine reacted once or twice with ethyleneoxide or with propylene oxide.

[0053] Decyl- or didecylamine reacted once or twice with ethylene oxideor with propylene oxide.

[0054] Isodecyl- or diisodecylamine reacted once or twice with ethyleneoxide or with propylene oxide.

[0055] Undecyl- or diundecylamine reacted once or twice with ethyleneoxide or with propylene oxide.

[0056] Isoundecyl- or diisoundecylamine reacted once or twice withethylene oxide or with propylene oxide.

[0057] Dodecyl- or didodecylamine reacted once or twice with ethyleneoxide or with propylene oxide.

[0058] Isododecyl- or diisododecylamine reacted once or twice withethylene oxide or with propylene oxide.

[0059] Tridecyl- or ditridecylamine reacted once or twice with ethyleneoxide or with propylene oxide.

[0060] Isotridecyl- or diisotridecylamine reacted once or twice withethylene oxide or with propylene oxide.

[0061] Tetradecyl- or ditetradecylamine reacted once or twice withethylene oxide or with propylene oxide.

[0062] Hexadecyl- or dihexadecylamine reacted once or twice withethylene oxide or with propylene oxide.

[0063] Octadecyl- or dioctadecylamine reacted once or twice withethylene oxide or with propylene oxide.

[0064] Eicosyl- or dieicosylamine reacted once or twice with ethyleneoxide or with propylene oxide.

[0065] Docosyl- or didocosylamine reacted once or twice with ethyleneoxide or with propylene oxide.

[0066] N-Methylbutylamine reacted with ethylene oxide or with propyleneoxide.

[0067] N-Ethylbutylamine reacted with ethylene oxide or with propyleneoxide.

[0068] Allyl- or diallylamine reacted once or twice with ethylene oxideor with propylene oxide.

[0069] Crotyl- or dicrotylamine reacted once or twice with ethyleneoxide or with propylene oxide.

[0070] Octadecenyl- or dioctadecenylamine reacted once or twice withethylene oxide or with propylene oxide.

[0071] Benzyl- or dibenzylamine reacted once or twice with ethyleneoxide or with propylene oxide.

[0072] Cyclohexyl- or dicyclohexylamine reacted once or twice withethylene oxide or with propylene oxide.

[0073] N-Methylcyclohexylamine reacted with ethylene oxide or withpropylene oxide.

[0074] N-Ethylcyclohexylamine reacted with ethylene oxide or withpropylene oxide.

[0075] 4-Vinyl-1-cyclohexene diepoxide reacted twice with diethanol- ordiisopropanolamine.

[0076] Dicyclopentadiene diepoxide reacted twice with diethanol- ordiisopropanolamine.

[0077] Bisphenol A diglycidyl ether reacted twice with diethanol- ordiisopropanolamine.

[0078] Trisglycidyl isocyanurate reacted three times with diethanol- ordiisopropanolamine.

[0079] Preference is given to trialkanolamines andmonoalkyl/alkenyldialkanolamines and alkanolamines where R³ _(a) and R³_(b)=independently of one another H or methyl and y=1.

[0080] According to the invention it is also possible to use compoundsof the general formula (I) where x=2, i.e. compounds which have twohydroxyalkylamino groups per molecule. Examples of these areN,N,N′,N′-tetrakis(2-hydroxyethyl)ethylenediamine,N,N,N′,N′-tetrakis(2-hydroxy-1-propyl)ethylenediamine,N,N,N′,N′-tetrakis(2-hydroxyethyl)propylenediamine andN,N,N′,N′-tetrakis(2-hydroxy-1-propyl)propylenediamine andN,N,N′,N′-tetrakis(2-hydroxyethyl)hexamethylenediamine, preference beinggiven to four-fold reactions of 1,6-hexamethylene- or1,8-octamethylenediamine or neopentanediamine with ethylene oxide orwith propylene oxide, or analogous reactions ofbisaminomethylcyclohexane or isophoronediamine or4,4′-diaminodicyclohexylmethane or3,3′-dimethyl-4,4′-diaminodicyclohexylmethane.

[0081] According to the invention, it is also possible to use compoundsof the general formula (I) where x=3, i.e. those which have threehydroxyalkylamino groups per molecule. An example of these is a reactionproduct of trisglycidyl isocyanurate with mono- or diethanolamine ormono- or dipropanolamine.

[0082] The alkanolamines of the general formula (I) are chemicals whichcan be purchased or can be prepared by known methods via N-alkylation ofan appropriate amine or ammonia (cf. Kirk-Othmer, Vol. 2,Alkanolamines).

[0083] Examples of the preferred alkanolamines of the general formula(I) are tris(2-hydroxyethyl)amine, tris(2-hydroxy-1-propyl)amine,bis(2-hydroxyethyl)-2-hydroxy-1-propylamine,N-n-butyl-N,N-bis(2-hydroxyethyl)amine,N,N-bis(n-butyl)-N-(2-hydroxyethyl)amine,N-(3-n-butyloxy-2-hydroxy-1-propyl)-N,N-bis(2-hydroxy-ethyl)amine,N-(1,3-dihydroxy-2-hydroxymethyl-2-propyl)-N,N-bis(2-hydroxyethyl)amine,N,N-bis(2-hydroxyethyl)-N-palmitylamine,N,N-bis(2-hydroxy-ethyl)-N-oleylamine,N,N-bis(2-hydroxyethyl)-N-stearylamine,N,N-bis(2-hydroxyethyl)-N-stearylamine, N-(2-hydroxyethyl)morpholine andN-(2,3-dihydroxy-1-propyl)morpholine, bishydroxyethylpiperazine andbishydroxyisopropylpiperazine and reaction products of glycidyl etherswith mono- or dialkylamine or ammonia, and also the alkanolaminesderived therefrom, for example ethanolamine, diethanolamine, mono- anddi-n-propanolamine, and mono- and diisopropanolamine.

[0084] Particular preference is also given to addition products ofolefins oxides, such as butene oxide, butadiene oxide, hexene oxide,hexadiene oxide, octene oxide, octadiene oxide, decene oxide, dodeceneoxide, tetradecene oxide, hexadecene oxide, octadecene oxide, eicoseneoxide and docosene oxide, and also to epoxystearyl alcohol withdiethanol- or diisopropanolamine, and also to other compounds with OHfunction in the β-position, for exampleN-(2-hydroxyhexadecyl)diethanolamine,N-(2-hydroxy-3-octyl(oxypropyl)diethanolamine,N-(2-hydroxy-3-decyloxypropyl)diethanolamine,N-(2-hydroxy-3-octyloxypropyl)diethanolamine andbis-N-(2-hydroxy-3-phenyloxypropyl)ethanolamine.

[0085] This list is given merely by way of example.

[0086] The perchlorates are known to the skilled worker. Examples arethose of the formula M(ClO₄)n, where M is H, Li, Na, K, Mg, Ca, Sr, Ba,Zn, Al, La, Ce or NH₄; n is 1, 2 or 3 as required by the valency of M.Aqueous ammonium perchlorate solutions or aqueous perchloric acidsolutions may also be used in the use of the invention in an aqueouspolymerization medium.

[0087] Various commonly used supply forms (formulations) of theperchlorates may be used here; for example as salt or solution in wateror in an organic solvent. Other examples of these perchlorateformulations are perchlorates dissolved or complexed using alcohols(polyols, cyclodextrins) or using ether alcohols or ester alcohols orcrown ethers. Other embodiments are described in EP 0 394 547, EP 0 457471 and WO 94/24200.

[0088] It is preferable to use the salts sodium/potassium perchlorate.

[0089] The prestabilized polymer compositions prepared by theseprocesses are likewise provided by the invention and feature intimatemixing, not previously achieved, of the halogen-containing polymer withthe stabilizer system before they have undergone any thermal stress. Thefirst step hitherto needed of incorporation of the stabilizer mixture isthus omitted, while the polymer prepared is directly ready for use. Thedistribution of the stabilizer mixture in the polymer here is almosthomogeneous. The polymer compositions of the invention includedispersions of the prestabilized polymers and the prestabilized polymersin dry form.

[0090] It is advantageous to use from 0 to 8 parts by weight, preferablyfrom 0.05 to 5 parts by weight, in particular from 0.1 to 2 parts byweight, of the compounds of the general formula (I) listed under (b),based on 100 parts by weight of PVC, to achieve stabilization in thechlorine-containing polymer in these compositions. The amount used ofthe perchlorates listed under (a) may be from 0.01 to 3 parts by weight,particularly preferably from 0.01 to 2 parts by weight, based on 100parts by weight of PVC. Finally, use may be made of amounts of from 0.01to 5 parts by weight, preferably from 0.1 to 2 parts by weight, of thesalts of a) and b) listed under c).

[0091] The invention also provides a process for preparing ready-to-usepolymer mixtures (compounded materials) in which, after theprestabilization of the invention, subsequent additional stabilizationof the polymer takes place using conventional stabilizers and/oradditives. The result is ready-to-use polymer mixtures in which furtherstabilizers and/or additives were added to a previously heat-stabilized,prestabilized polymer. These polymer mixtures, which are also includedwithin the invention, feature optimized thermal and optical properties,an example being that the prestabilization has a favourable effect onthe starting colour when the initial thermal stress occurs.

[0092] Examples of stabilizers and/or additives which can be used in thepost-stabilization process are phosphites, polyols and disaccharidealcohols, glycidyl compounds, hydrotalcites, zeolites (aluminosilicatesof alkali metals or of alkaline earth metals), fillers, metal soaps,other compounds of alkali metals or of alkaline earth metals,fillers/pigments, lubricants, plasticizers, pigments, epoxidized fattyesters, and other epoxy compounds, antioxidants, UV absorbers, lightstabilizers, optical brighteners, wetting agents, antisettling agentsand blowing agents. Examples of these additional components are listedand illustrated below (cf. “Handbook of PVC-Formulating” by E. J.Wickson, John Wiley & Sons, New York 1993).

[0093] Polyols and Disaccharide Alcohols

[0094] Examples of possible compounds of this type are:

[0095] pentaerythritol, dipentaerythritol, tripentaerythritol,trimethylolethane, bis(trimethylolpropane), polyvinyl alcohol,bis(trimethylolethane), trimethylolpropane, sugars, sugar alcohols. Ofthese, preference is given to the disaccharide alcohols. It is alsopossible to use polyol syrups, such as sorbitol syrup, mannitol syrupand maltitol syrup.

[0096] Examples of the amounts of the polyols used are from 0.01 to 20parts by weight, advantageously from 0.1 to 20 parts by weight and inparticular from 0.1 to 10 parts by weight, based on 100 parts by weightof PVC.

[0097] Glycidyl Compounds

[0098] These contain the glycidyl group

[0099] bonded directly to carbon, oxygen, nitrogen or sulphur atoms,either where both of R₁ and R₃ are hydrogen, R₂ is hydrogen or methyland n=0 or where R₁ and R₃ together are —CH₂—CH₂— or —CH₂—CH₂—CH₂—, R₂then being hydrogen and n being 0 or 1.

[0100] It is preferable to use glycidyl compounds having two functionalgroups. However, it is also possible in principle to use glycidylcompounds having one, three or more functional groups.

[0101] Use is predominantly made of diglycidyl compounds having aromaticgroups.

[0102] The amounts used of the terminal epoxy compounds are preferablyat least 0.1 part, preferably from 0.1 to 50 parts by weight,advantageously from 1 to 30 parts by weight and in particular from 1 to25 parts by weight, based on 100 parts by weight of PVC.

[0103] Hydrotalcites

[0104] The chemical composition of these compounds is known to theskilled worker, e.g. from the patents DE 3 843 581, U.S. Pat. No.4,000,100, EP 0 062 813 and WO 93/20135. Compounds from the hydrotalciteseries may be described by the following general formula

[0105] M²⁺ _(1−x)M³⁺ _(x)(OH)₂ (A^(b−))_(x/b).d H₂O,

[0106] where

[0107] M²⁺=one or more of the metals selected from the group consistingof Mg, Ca, Sr, Zn and Sn,

[0108] M³⁺=Al or B,

[0109] A^(n) an anion of valency n,

[0110] b is a number from 1 to 2,

[0111] 0<x<0.5,

[0112] d is a number from 0 to 20.

[0113] Preference is given to compounds with

[0114] A^(n)=OH⁻—, ClO₄ ⁻, HCO₃ ⁻, CH₃COO⁻, C₆H₅COO⁻, CO₃ ²⁻,

[0115] (CHOHCOO)₂ ²⁻, (CH₂COO)₂ ²⁻, CH₃CHOHCOO⁻, HPO₃ ⁻ or HPO₄ ²⁻.

[0116] Examples of hydrotalcites are

[0117] Al₂O₃.6MgO.CO₂.12H₂O (i), Mg_(4.5)Al₂(OH)₁₃.CO₃.3.5H₂O (ii),

[0118] 4MgO.Al₂O₃.CO₂.9H₂O (iii), 4MgO.Al₂O₃.CO₂.6H₂O,

[0119] ZnO.3MgO.Al₂O₃.CO₂.8-9H₂O and ZnO.3MgO.Al₂O₃.CO₂.5-6H₂O.

[0120] Very particular preference is given to the types Alkamizer 2,Alkamizer P 93-2 (ex Kyowa) and L-CAM (lithium-modified hydrotalcite exFuji). It is preferable to use dehydrated hydrotalcites.

[0121] Zeolites (Aluminosilicates of Alkali Metals and/or of AlkalineEarth Metals)

[0122] These may be described by the following general formulaM_(x/n)[(AlO₂)_(x)(SiO₂)_(y)].wH₂O,

[0123] where n is the charge on the cation M;

[0124] M is an element of the first or second main group, such as Li,Na, K, Mg, Ca, Sr or Ba;

[0125] y: x is a number from 0.8 to 15, preferably from 0.8 to 1.2; and

[0126] w is a number from 0 to 300, preferably from 0.5 to 30.

[0127] Examples of zeolites are sodium aluminosilicates of the formulae

[0128] Na₁₂Al₁₂Si₁₂O₄₈.27 H₂O [zeolite A], Na₆Al₆Si₆O₂₄.2 NaX.7.5 H₂O,X═OH, halogen,

[0129] ClO₄ [sodalite]; Na₆Al₆Si₃₀O₇₂.24 H₂O; Na₈Al₈Si₄₀O₉₆.24 H₂O;Na₁₆Al₁₆Si₂₄O₈₀.16 H₂O; Na₁₆Al₁₆Si₃₂O₉₆.16 H₂O; Na₅₆Al₅₆Si₁₃₆O₃₈₄.250H₂O [zeolite Y],

[0130] Na₈₆Al₈₆Si₁₀₆O₃₈₄.264 H₂O [zeolite X];

[0131] or the zeolites which can be prepared by partial or completeexchange of the Na atoms by Li atoms, K atoms, Mg atoms, Ca atoms, Sratoms or Zn atoms, for example

[0132] (Na,K)₁₀Al₁₀Si₂₂O₆₄.20 H₂O; Ca_(4.5)Na₃[(AlO₂)₁₂(SiO₂)₁₂].30 H₂O;

[0133] KgNa₃[(AlO₂)₁₂(SiO₂)₁₂].27 H₂O.

[0134] Very particular preference is given to Na zeolite A and Nazeolite P.

[0135] The hydrotalcites and/or zeolites may be used in amounts of, forexample, 0.1 to 20 parts by weight, expediently 0.1 to 10 parts byweight and in particular 0.1 to 5 parts by weight, based on 100 parts byweight of halogen-containing polymers.

[0136] Fillers

[0137] Fillers such as calcium carbonate, dolomite, wollastonite,magnesium oxide, magnesium hydroxide, silicates, china clay, talc, glassfibres, glass beads, wood flour, mica, metal oxides or metal hydroxides,carbon black, graphite, rock flour, heavy spar, glass fibres, talc,kaolin and chalk are used. Preference is given to chalk (HANDBOOK OF PVCFORMULATING E. J. Wickson, John Wiley & Sons, Inc., 1993, pp. 393-449)and reinforcing agents (TASCHENBUCH der Kunststoffadditive [PlasticsAdditives Handbook], R. Gächter & H. Müller, Carl Hanser, 1990, pp.549-615).

[0138] The fillers may be used in amounts of preferably at least onepart by weight, for example 5 to 200 parts by weight, expediently 5 to150 parts by weight and in particular from 5 to 100 parts by weight,based on 100 parts by weight of PVC.

Metal Soaps

[0139] Metal soaps are primarily metal carboxylates, preferably ofrelatively long-chain carboxylic acids. Well-known examples of these arestearates and laurates, and also oleates and salts of relativelyshort-chain aliphatic or aromatic carboxylic acids, such as acetic acid,propionic acid, butyric acid, valeric acid, hexanoic acid, sorbic acid;oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid,fumaric acid, citric acid, benzoic acid, salicylic acid, phthalic acids,hemimellitic acid, trimellitic acid, pyromellitic acid.

[0140] Metals which should be mentioned are: Li, Na, K, Mg, Ca, Sr, Ba,Zn, Al, La, Ce and rare earth metals. Use is frequently made ofso-called synergistic mixtures, such as barium/zinc stabilizers,magnesium/zinc stabilizers, calcium/zinc stabilizers orcalcium/magnesium/zinc stabilizers. The metal soaps may be used eitheralone or in mixtures. An overview of common metal soaps is found inUllmann's Encyclopedia of Industrial Chemistry, 5th Ed., Vol. A16(1985), pp. 361 et seq.

[0141] The metal soaps or mixtures of these may be used in amounts of,for example, 0.001 to 10 parts by weight, expediently 0.01 to 8 parts byweight, particularly preferably 0.05 to 5 parts by weight, based on 100parts by weight of PVC.

[0142] Alkali Metal and Alkaline Earth Metal Compounds

[0143] For the purposes of the present invention, these are mainly thecarboxylates of the acids described above, but also corresponding oxidesor, respectively, hydroxides or carbonates. Mixtures of these withorganic acids are also possible. Examples are LiOH, NaOH, KOH, CaO,Ca(OH)₂, MgO, Mg(OH)₂, Sr(OH)₂, Al(OH)₃, CaCO₃ and MgCO₃ (and also basiccarbonates, such as magnesia alba and huntite), and also fatty-acidsalts of Na and of K. In the case of alkaline earth carboxylates and Zncarboxylates it is also possible to use adducts of these with MO orM(OH)₂ (M=Ca, Mg, Sr or Zn), so-called “overbased” compounds. Inaddition to the stabilizers according to the invention it is preferableto use alkali metal carboxylates, alkaline earth metal carboxylatesand/or aluminium carboxylates.

[0144] Lubricants

[0145] Examples of possible lubricants are: montan wax, fatty esters, PEwaxes, amide waxes, chloroparaffins, glycerol esters and alkaline earthmetal soaps, and fatty ketones, and also the lubricants, or combinationsof the lubricants, listed in EP 0 259 783. Calcium stearate ispreferred.

[0146] Plasticizers

[0147] Examples of organic plasticizers are those from the followinggroups:

[0148] A) Phthalates: such as preferably di-2-ethylhexyl, diisononyl anddiisodecyl phthalate, also known by the common abbreviations DOP(dioctyl phthalate, di-2-ethylhexylphthalate), DINP (diisononylphthalate), DIDP (diisodecyl phthalate).

[0149] B) Esters of aliphatic dicarboxylic acids, in particular estersof adipic, azelaic, and sebacic acid: preferably di-2-ethylhexyl adipateand diisooctyl adipate.

[0150] C) Trimellitic esters, such as tri-2-ethylhexyl trimellitate,triisodecyl trimellitate (mixture), triisotridecyl trimellitate,triisooctyl trimellitate (mixture), and also tri-C₆-C₈-alkyl,tri-C₆-C₁₀-alkyl, tri-C₇-C₉-alkyl and tri-C₉-C₁₁-alkyl trimellitate.Common abbreviations are TOTM (trioctyl trimellitate, tri-2-ethylhexyltrimellitate), TIDTM (triisodecyl trimellitate) and TTTDTM(triisotridecyl trimellitate).

[0151] D) Epoxy plasticizers: these are primarily epoxidized unsaturatedfatty acids, e.g. epoxidized soybean oil.

[0152] E) Polymeric plasticizers: the commonest starting materials forpreparing polyester plasticizers are: dicarboxylic acids, such asadipic, phthalic, azelaic or sebacic acid; diols, such as1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol,neopentyl glycol and diethylene glycol.

[0153] F) Phosphoric esters: a definition of these esters is given inthe abovementioned “Taschenbuch der Kunststoffadditive” [“PlasticsAdditives Handbook”], Chapter 5.9.5, pp. 408-412. Examples of thesephosphoric esters are tributyl phosphate, tri-2-ethylbutyl phosphate,tri-2-ethylhexyl phosphate, trichloroethyl phosphate, 2-ethylhexyldiphenyl phosphate, cresyl diphenyl phosphate, triphenyl phosphate,tricresyl phosphate and trixylenyl phosphate. Preference is given totris(2-ethylhexyl) phosphate and Reofos® 50 and 95 (CibaSpezialitätenchemie).

[0154] G) Chlorinated hydrocarbons (paraffins)

[0155] H) Hydrocarbons

[0156] I) Monoesters, e.g. butyl oleate, phenoxyethyl oleate,tetrahydrofurfuryl oleate and alkylsulphonates.

[0157] J) Glycol esters, e.g. diglycol benzoates.

[0158] A definition of these plasticizers and examples for the same aregiven in “Kunststoffadditive” [“Plastics Additives”], R. Gächter/H.Müller, Carl Hanser Verlag, 3rd Ed., 1989, Chapter 5.9.6, pp. 412-415,and in “PVC Technology”, W. V. Titow, 4th Ed., Elsevier Publ., 1984, pp.165-170. It is also possible to use mixtures of different plasticizers.

[0159] The plasticizers may be used in amounts of, for example, 5 to 20parts by weight, expediently 10 to 20 parts by weight, based on 100parts by weight of PVC. Rigid or semirigid PVC preferably comprises upto 10%, particularly preferably up to 5%, of plasticizer, or noplasticizer.

[0160] Pigments

[0161] Suitable substances are known to the skilled worker. Examples ofinorganic pigments are TiO₂, pigments based on zirconium oxide, BaSO₄,zinc oxide (zinc white) and lithopones (zinc sulphide/barium sulphate),carbon black, carbon black-titanium dioxide mixtures, iron oxidepigments, Sb₂O₃, (Ti,Ba,Sb)O₂, Cr₂O₃, spinels, such as cobalt blue andcobalt green, Cd(S,Se), ultramarine blue. Examples of organic pigmentsare azo pigments, phthalocyanine pigments, quinacridone pigments,perylene pigments, diketopyrrolopyrrole pigments and anthraquinonepigments. TiO₂ in micronized form is also preferred. A definition andfurther descriptions are found in the “Handbook of PVC Formulating”, E.J. Wickson, John Wiley & Sons, New York, 1993.

[0162] Phosphites

[0163] Organic phosphites are known costabilizers forchlorine-containing polymers. Examples of these are trioctyl, tridecyl,tridodecyl, tritridecyl, tripentadecyl, trioleyl, tristearyl, triphenyl,trilauryl, tricresyl, tris(nonylphenyl), tris(2,4-tert-butylphenyl) andtricyclohexyl phosphite.

[0164] Other suitable phosphites are various mixed aryl dialkyl or alkyldiarylphosphites, such as phenyl dioctyl, phenyl didecyl, phenyldidodecyl, phenyl ditridecyl, phenyl ditetradecyl, phenyl dipentadecyl,octyl diphenyl, decyl diphenyl, undecyl diphenyl, dodecyl diphenyl,tridecyl diphenyl, tetradecyl diphenyl, pentadecyl diphenyl, oleyldiphenyl, stearyl diphenyl and dodecyl bis(2,4-di-tert-butylphenyl)phosphite. Advantageous use may also be made of phosphites of variousdi- or polyols: e.g. tetraphenyldipropylene glycol diphosphite,poly(dipropylene glycol) phenyl phosphite, tetraisodecyl dipropyleneglycol diphosphite, tris(dipropylene glycol) phosphite,tetramethylolcyclohexanol decyl diphosphite, tetramethylolcyclohexanolbutoxyethoxyethyl diphosphite, tetramethylolcyclohexanol nonylphenyldiphosphite, bis(nonylphenyl) di(trimethylolpropane) diphosphite,bis(2-butoxyethyl) di(trimethylolpropane) diphosphite,tris(hydroxyethyl) isocyanurate hexadecyl triphosphite, didecylpentaerythrityl diphosphite, distearyl pentaerythrityl diphosphite,bis(2,4-di-tert-butylphenyl) pentaerythrityl diphosphite, and alsomixtures of these phosphites and aryl/alkyl phosphite mixtures ofempirical composition (H₁₉C₉—C₆H₄O)_(1.5)P(OC_(12,13)H_(25,27))_(1.5) or[C₈H₁₇—C₆H₄—O—]₂P[i-C₈H₁₇O],(H₁₉C₉—C₆H₄O)_(1.5)P(OC_(9,11)H_(19,23))_(1.5).

[0165] Examples of the amounts of the organic phosphites used are from0.01 to 10 parts by weight, advantageously from 0.05 to 5 parts byweight and in particular from 0.1 to 3 parts by weight, based on 100parts by weight of PVC.

[0166] Epoxidized Fatty Acid Esters and Other Epoxy Compounds

[0167] The stabilizer combination of the invention may additionally andpreferably comprise at least one epoxidized fatty acid ester. Possiblecompounds here are especially esters of fatty acids from natural sources(fatty acid glycerides), such as soya oil or rapeseed oil. However, itis also possible to use synthetic products, such as epoxidized butyloleate. Use may also be made of epoxidized polybutadiene andpolyisoprene, if desired also in a partially hydroxylated form, or ofglycidyl acrylate and glycidyl methacrylate as homo- or copolymer. Theseepoxy compounds may also have been applied to an alumino salt compound;in this connection see also DE-A-4 031 818.

[0168] Antioxidants

[0169] Alkylated monophenols, e.g. 2,6-di-tert-butyl-4-methylphenol,alkylthiomethylphenols, e.g. 2,4-dioctylthiomethyl-6-tert-butylphenol,alkylated hydroquinones, e.g. 2,6-di-tert-butyl-4-methoxyphenol,hydroxylated thiodiphenyl ethers, e.g.2,2′-thiobis(6-tert-butyl-4-methylphenol), alkylidenebisphenols, e.g.2,2′-methylenebis(6-tert-butyl-4-methylphenol), benzyl compounds, e.g.3,5,3′,5′-tetratert-butyl-4,4′-di-hydroxydibenzyl ether,hydroxybenzylated malonates, e.g. dioctadecyl2,2-bis(3,5-di-tert-butyl-2-hydroxybenzyl) malonate, hydroxybenzylaromatics, e.g.1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene,triazine compounds, e.g.2,4-bis-octylmercapto-6-(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine,phosphonates and phosphonites, e.g. dimethyl2,5-di-tert-butyl-4-hydroxybenzylphosphonate, acylaminophenols, e.g.4-hydroxylauranilide, esters ofbeta-(3,5-ditert-butyl-4-hydroxyphenyl)propionic acid,beta-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acid,beta-(3,5-dicyclohexyl-4-hydroxyphenyl)propionic acid, esters of3,5-ditert-butyl-4-hydroxyphenylacetic acid with mono- or polyhydricalcohols, amides of beta-(3,5-ditert-butyl-4-hydroxyphenyl)propionicacid, for example,N,N′-bis(3,5-ditert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamine,vitamin E (tocopherol) and derivatives.

[0170] Examples of the amounts of the antioxidants used are from 0.01 to10 parts by weight, advantageously from 0.1 to 10 parts by weight and inparticular from 0.1 to 5 parts by weight, based on 100 parts by weightof PVC.

[0171] UV Absorbers and Light Stabilizers

[0172] Examples of these are: 2-(2′-hydroxyphenyl)benzotriazoles, suchas 2-(2′-hydroxy-5′-methylphenyl)benzotriazole, 2-hydroxybenzophenones,esters of unsubstituted or substituted benzoic acids, such as4-tert-butylphenyl salicylate, phenyl salicylate, acrylates, nickelcompounds, oxalamides, such as 4,4′-dioctyloxyoxanilide,2,2′-dioctyloxy-5,5′-ditert-butyloxanilide,2-(2-hydroxyphenyl)-1,3,5-triazines, such as2,4,6-tris(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,sterically hindered amines, such asbis(2,2,6,6-tetramethylpiperidin-4-yl) sebacate,bis(2,2,6,6-tetra-methylpiperidin-4-yl) succinate.

[0173] Blowing Agents

[0174] Examples of blowing agents are organic azo compounds and organichydrazo compounds, tetrazoles, oxazines, isatoic anhydride, and alsosoda and sodium bicarbonate. Preference is given to azodicarbonamide andsodium bicarbonate and also mixtures of these.

[0175] Definitions for and examples of impact modifiers and processingaids, gelling agents, antistats, biocides, metal deactivators, opticalbrighteners, flame retardants, antifogging agents and compatibilizersare given in “Kunststoffadditive” [“Plastics Additives”], R. Gächter/H.Müller, Carl Hanser Verlag, 3rd Ed., 1989, and 4th Ed. 2001, and in“Handbook of Polyvinyl Chloride Formulating” E. J. Wilson, J. Wiley &Sons, 1993, and also in “Plastics Additives” G. Pritchard, Chapman &Hall, London, 1st edition, 1998.

[0176] Impact modifiers are also described in detail in “ImpactModifiers for PVC”, J. T. Lutz/D. L. Dunkelberger, John Wiley & Sons,1992.

[0177] Examples of the prestabilized chlorine-containing polymers to beprepared are: polymers of vinyl chloride, of vinylidene chloride, vinylresins whose structure contains vinyl chloride units, for examplecopolymers of vinyl chloride and vinyl esters of aliphatic acids, inparticular vinyl acetate, copolymers of vinyl chloride with esters of(meth)acrylic acid and with acrylonitrile, copolymers of vinyl chloridewith diene compounds and with unsaturated dicarboxylic acids oranhydrides of these, for example copolymers of vinyl chloride withdiethyl maleate, diethyl fumarate, or maleic anhydride, post-chlorinatedpolymers and copolymers of vinyl chloride, copolymers of vinyl chlorideand of vinylidene chloride with unsaturated aldehydes, ketones and othercompounds, for example acrolein, crotonaldehyde, vinyl methyl ketone,vinyl methyl ether, vinyl isobutyl ether, and the like; polymers ofvinylidene chloride and copolymers of the same with vinyl chloride andwith other polymerizable compounds; polymers of vinyl chloroacetate andof dichlorodivinyl ether; chlorinated polymers of vinyl acetate,chlorinated polymeric esters of acrylic acid and of alpha-substitutedacrylic acid; polymers of chlorinated styrenes, such as dichlorostyrene;chlorinated rubbers; chlorinated polymers of ethylene; polymers andpost-chlorinated polymers of chlorobutadiene and copolymers of thesewith vinyl chloride, chlorinated natural and synthetic rubbers, andmixtures of the polymers mentioned with each other or with otherpolymerizable compounds. For the purposes of this invention, PVCincludes copolymers with polymerizable compounds, such as acrylonitrile,vinyl acetate, or ABS, and the materials may involve suspension, bulk oremulsion polymers.

[0178] Preference is given to a PVC homopolymer or a PVC homopolymercombined with polyacrylates.

[0179] Use may also be made of graft polymers of PVC with EVA, ABS andMBS. Other preferred substrates are mixtures of the abovementioned homo-and copolymers, in particular vinyl chloride homopolymers, with otherthermoplastic and/or elastomeric polymers, in particular blends withABS, MBS, NBR, SAN, EVA, CPE, MBAS, PMA, PMMA, EPDM and withpolylactones, in particular those from the group ABS, NBR, NAR, SAN andEVA. The abbreviations used for the copolymers are familiar to theskilled worker and have the following meaning: ABS:acrylonitrile-butadienestyrene; SAN: styrene-acrylonitrile; NBR:acrylonitrile-butadiene; NAR: acrylonitrile-acrylate; EVA:ethylene-vinyl acetate. Other particular materials which may be used areacrylate-based styrene-acrylonitrile copolymers (ASA).

[0180] Polymer compositions which comprise a mixture of from 25 to 75%by weight of PVC and 75 to 25% by weight of the copolymers mentioned ascomponents (i) and (ii) are preferred here. Compositions composed of (i)100 parts by weight of PVC and (ii) from 0 to 300 parts by weight of ABSand/or SAN-modified ABS and from 0 to 80 parts by weight of thecopolymers NBR, NAR and/or EVA, PMA, PMMA, but in particular EVA, PMAand PMMA, are a particularly important component.

[0181] The compounds which may be used concomitantly according to theinvention, and also the chlorine-containing polymers, are well known tothe skilled worker and are described in detail in “Kunstoffadditive”[Plastics additives], R. Gächter/H. Müller, Carl Hanser Verlag, 3rd and4th edn., 1989 and 2001; and in DE 197 41 778 and EP-A 99 105 418.0 of17.03.1999, expressly incorporated herein by way of reference.

[0182] The monomers are polymerized by traditional emulsion orsuspension polymerization. More details on the polymerization processcan be found in DE 1 269 350 or EP 0 281 210. The commonly usedpolymerization initiators are mostly peroxidic or azo compounds used asfree-radical initiators. Examples of these are: persulphates, organicand inorganic peroxide salts, hydrogen peroxide, percarbonates andperesters, benzoyl peroxide, ketone peroxides, polyester peroxides,polyether peroxides, cyclohexanone peroxide, methyl ethyl ketoneperoxide, cumyl hydroperoxide, diacyl peroxides, and tert-butylhydroperoxides. The prestabilization of the Invention can be used withany of the industrially relevant processes for polymerization ofhalogen-containing monomers.

[0183] The stabilizer system is added to or dissolved In thepolymerization medium by the usual laboratory methods, directly in theform of a solid or mixture of solids, or in the form of a solution ordispersion in a suspension medium or, respectively, solvent compatiblewith the polymerization medium. The addition may take place prior to,during, or after the polymerization.

[0184] The following methods may be used to incorporate the stabilizersand/or additives into the prestabilized polymers: an emulsion ordispersion method (one example being the use of a mixture which is apaste); a dry mixture method during the mixing of additional components;a method with direct addition to the process apparatus (e.g. calender,mixer, kneader, extruder or the like) or a method involving a solutionor melt or what are known as flakes or pellets in dust-free or one-packform.

[0185] The ready-to-use polymer mixtures comprising all of theadditives, known as compounded polymer materials, may be prepared in amanner known per se, and to this end use is made of apparatus known perse, such as the abovementioned process apparatus, to mix furtherstabilizers and/or additives with the prestabilized PVC. Thesestabilizers or additives may be added individually or in a mixture, orelse in the form of what are known as masterbatches.

[0186] The ready-to-use PVC prepared by the present invention may bebrought to the desired form by known methods. Examples of theseprocesses are milling, calendering, extruding, injection moulding andspinning, and extrusion with blowing. The stabilized PVC may also beprocessed to give foams.

[0187] Examples of uses for which a ready-to-use PVC prepared by thepresent invention is particularly suitable are hollow articles(bottles), packaging films (thermoforming films), blown films, pipes,foams, heavy profiles (window frames), thin-wall profiles, constructionprofiles, films (including Luvitherm), PVC pipes, profiles, sidings,fittings, office sheeting and apparatus housings (computers, householddevices). The PVC of the invention is particularly suitable forsemirigid and flexible formulations, in particular in the form offlexible formulations for cable sheathing, cable insulation,floorcoverings, wallpapers, motor vehicle components, flexible films,injection mouldings, and hoses, these being particularly preferred. Inthe form of semirigid formulations the PVC of the invention isparticularly suitable for decorative films, foams, agriculturalsheeting, hoses, sealing profiles and office sheeting.

[0188] Examples of the application of the PVC of the invention as aplastisol are synthetic leather, floorcoverings, textile coatings,wallpapers, coil coatings and underbody protection for motor vehicles.

[0189] Examples of sintered PVC applications of the stabilizedready-to-use PVC of the invention are slush, slush-mould and coilcoatings for plastisol formulations, semirigid formulations and flexibleformulations.

[0190] For more details in this connection see “Kunststoffhandbuch PVC”[Plastics Handbook PVC], volume 2/2, W. Becker/H. Braun, 2nd edn., 1985,Carl Hanser Verlag, pages 1236-1277.

[0191] The examples below illustrate the invention but do not limit thesame. As in the remainder of the Description, parts and percentage dataare based on weight.

EXAMPLES

[0192] TABLE 1 Stabilizers used Stabilizer Name 1 Triethanolamine + 13%sodium perchlorate monohydrate 2 Triethanolamine 3 Sodium perchloratemonohydrate 4 Oleyldiethanolamine + 13% sodium perchlorate monohydrate 5Oleyldiethanolamine 6 Triisopropanolamine + 13% sodium perchloratemonohydrate 7 Triisopropanolamine 8 Tri-n-octylamine 9 Sodium carbonate10 Diphenylurea

Example 1

[0193] Preparation of Prestabilized PVC Powder

[0194] A suspension PVC (SPVC) was prepared in a 500 ml stainless steelautoclave from monomeric vinyl chloride (VCM) by free-radicalpolymerization. The process parameters were retained for all of theexperiments:

[0195] temperature: 57.2° C.

[0196] stirring rate: 1 800 rpm

[0197] suspension medium: 2% Methocel F-50 (hydroxypropylmethylcellulosein water, NOXOL (polyvinyl alcohol) as anticaking agent)

[0198] reaction time: about 210 min

[0199] conversion rate: about 80%.

[0200] Two different initiator systems were used for the free-radicalpolymerization.

[0201] Experimental series 1: Esperox 939 M (75% strength solution ofcumyl peroxyneodecanoate)

[0202] Experimental series 2: Espercarb S 840 M (75% strength solutionof di-2-ethylhexyl peroxydicarbonate)

[0203] (both being commercially available initiators from Crompton forfree-radical polymerization processes).

[0204] As shown in Table 2 the initiators were used at 0.1 or 0.12% byweight, based on VCM.

[0205] The stabilizers listed in Table 1—in each case 0.5% by weight,based on VCM—were added at various times, either at the start of thepolymerization or once conversion had reached about 80% (at the “end ofthe reaction”).

[0206] Once the polymerization process had ended, the solid polymer wasfiltered off, washed and dried to give a fine white powder, which wastested for thermal stability (DHC, statistical heat test) andprocessability (pasting+film production).

[0207] Thermal Stabilization Test/Dehydrochlorination Test

[0208] The PVC powder prepared in this way was subjected to adehydrochlorination test (DHC) to DIN 53381 at 180° C. (see Table 2.0).

[0209] Statistical Heat Test

[0210] 45 g of the “PVC powder”were roll-milled with 15 g of diisononylphthalate (DINP), 0.1 g of calcium stearate and 0.15 g of Loxiol G 71 S(pentaerythrityl adipate=complex ester lubricant) for 3 minutes at 180°C. Test strips of thickness 0.5 mm were taken from the resultant PVCsheet and the colour was then determined via Yellowness Index (YI) toASTM D1925-70 (see Tab. 2.0 and Tab. 2.1). TABLE 2.0 DHC of powderColour PVC 10 200 (YI value)* powder Initiator Stab. [μS/cm] [μS/cm] ofsheet 1) Esperox 939 M — 14 35 27.39 0.10% by weight 5) Espercarb S 840M —  8 27 21.87 0.12% by weight 9) Esperox 939 M 1

17 42 15.44 0.10% by weight 11)  Espercarb S 840 M 1

30 51 18.32 0.12% by weight 15)  Esperox 939 M 4

21 53 14.64 0.10% by weight

[0211] Experiments 9, 11 and 15 (according to the invention) show themarked superiority in terms of thermal stability (longer induction timesat 10 and 200 μS/cm) and the better starting colour of the sheetsproduced (YI values). TABLE 2.1 Discoloration Discoloration withoutpost- with post- stabilization stabilization** PVC (YI value)* (YIvalue)* powder Description Stab. 5 min 30 min 5 min 30 min Ref. EvipolSH 7020 Without 16  47 7 15  from EVC*** prestab. 15) Esperox 939 4

6 28 5 7 initiator 0.1% by weight 13) Esperox 939 1

8 40 5 7 initiator 0.1% by weight

[0212] It is clear that prestabilized PVC grades show marked advantageswhen use is made of conventional post-stabilization systems, and havemarkedly improved thermal stability even without post-stabilization.

Example 2

[0213] Preparation of PVC powder 3

[0214] A mixture made from 50 g of an aqueous dispersion composed ofabout 50% of solid PVC and 50% of water with additives such as4-alkylbenzenesulphonic acid derivative/antiblockingagent/polymerization auxiliary and 0.125 g of a stabilizer as describedin Table 1 was stirred at 80° C. for 60 minutes. This mixture was thendried in a crystallization dish at about 20° C. (powder 3).

[0215] Dehydrochlorination Test

[0216] The PVC powder thus prepared were then subjected to adehydrochlorination test (DHC) to DIN 53381 at 180° C. The results areseen in Table 3. TABLE 3 DHC 10 [μS/cm] Stabilizer min Withoutstabilizer 14 1 50 2 44 3 10 4 35 5 25 6 38 7 28 8 16 10 15

[0217] Each of the stabilizer mixtures which may be used according tothe invention shows a marked advantage over the individual components orabsence of stabilizers, this being apparent from the longer inductiontimes (10 [μS/cm]min).

Example 3

[0218] 20 g of “powder (3)” PVC powder were processed with 20 g ofdioctyl phthalate (DOP) in a dissolver to give a PVC paste and gelled ina Mathis oven at 190° C. to give a sheet of thickness 0.5 mm.

[0219] Statistical Heat Test

[0220] The Yellowness Index (YI) of this sheet was then determined toASTM D1925-70 (Table 4). Low YI values mean good stabilization andstarting colour. TABLE 4 Stabilizer YI value of sheet Without stabilizer11.65 1 6.05 2 6.98 3 8.77 4 6.56 5 8.30 6 6.02 7 8.26 8 9.07 9 8.43 1017.22

[0221] Each of the mixtures 1, 4 and 6 of the invention shows animproved starting colour (lower YI value) when compared with thereference 10 known from the literature or with the unstabilized sheet.

Example 4

[0222] Preparation of PVC powder 4

[0223] A mixture made from 50 g of an aqueous PVC dispersion composed ofabout 40% of solid PVC and 60% of water with additions of sorbitanester, polymerization auxiliaries, emulsifiers and 0.125 g of astabilizer as described in Table 1 was stirred at 80° C. for 60 minutes.This mixture was then dried in a crystallization dish at about 20° C.(PVC powder 4).

[0224] Dehydrochlorination Test

[0225] The PVC powder thus prepared was then subjected to adehydrochlorination test (DHC) to DIN 53381 at 180° C. (Table 5). TABLE5 DHC 10 [μS/cm] 200 [μS/cm] Stabilizer min min Without stabilizer 40 511 62 78 2 32 38 3 35 47 8 19 26 9 43 49 10 55 69

[0226] It is clearly apparent that, as previously described in Examples1 and 3, the stabilizer mixture 1 of the invention is more effectivethan the individual components and the stabilizers 9+10 described in theliterature, this being apparent from the longer induction times (10 and200 [μS/cm]min).

Example 5

[0227] 20 g of “powder (4)” PVC powder prepared as in Example 4 wereprocessed with 20 g of dioctyl phthalate in a dissolver to give a PVCpaste and gelled in a Mathis oven at 190° C. to give a sheet ofthickness 0.5 mm. Test strips of thickness 0.5 mm were taken from thissheet and heated at 180° C. in the Mathis oven, and the Yellowness Index(YI) to ASTM D1925-70 was determined at intervals of 2 minutes. TABLE 6Statistical heat test YI value after Stabilizer 2 min 10 min 24 minWithout stabilizer 8.02 16.30 Terminated 1  6.69 10.76 23.57 2* 7.8728.56 Terminated

[0228] As in Examples 2 and 3, it is again clear that PVC compositionswhich have been prepared by the process of the invention have highstability.

1. A process for preparing a stabilized suspension/emulsion polymer ofhalogen-containing monomers comprising adding a polymer thermalstabilizer mixture compatible with the polymerization medium prior to,during or directly after the polymerization process prior to isolationof the polymer.
 2. The process of claim 1,—wherein the polymer thermalstabilizer mixture comprises perchlorate compounds and/or alkanolaminesand/or salts of these.
 3. The process of claim 1 wherein the polymerthermal stabilizer mixture comprises at least a) a perchlorate and/or b)an alkanolamine of the formula (I)

where x=1, 2 or 3; y=1, 2, 3, 4, 5 or 6; n=from 1 to 10; R¹ andR²=independently of one another H, C₁-C₂₂-alkyl, -[—(CHR³ _(a))_(y)-CHR³_(b)-O—]_(n)-H, -[—(CHR³ _(a))_(y)-CHR³ _(b)-O—]_(n)-CO—R⁴,C₂-C₂₀-alkenyl, C₂-C₁₈-acyl, C₄-C₈-cycloalkyl, where this may have OHsubstitution in the β-position, C₆-C₁₀-aryl, C₇-C₁₀-alkaryl orC₇-C₁₀-aralkyl, or, if x=1, R¹ and R² may also, together with the N,form a closed ring having from 4 to 10 members, composed of carbon atomsand, where appropriate, of up to 2 heteroatoms, or if x=2, R¹ may alsobe C₂-C₁₈-alkylene which, at both β-carbon atoms, may have OHsubstitution and/or have interruption by one or more O atoms and/or oneor more NR² groups, or be dihydroxy-substitutedtetrahydrodicyclopentadienylene, dihydroxy-substitutedethylcyclohexanylene, dihydroxy-substituted 4,4′-(bisphenol A dipropylether)ylene, isophoronylene, dimethylcyclohexanylene,dicyclohexylmethanylene or 3,3′-dimethyldicyclohexylmethanylene, and ifx=3, R¹ may also be trihydroxy-substituted (tri-N-propylisocyanurate)triyl; R³ _(a) and R³ _(b)=independently of one anotherC₁-C₂₂-alkyl, C₂-C₆-alkenyl, C₆-C₁₀-aryl, H or CH₂—X—R⁵, where X═O, S,—O—CO— or —CO—O—; R⁴═C₁-C₁₈-alkyl/alkenyl or phenyl; and R⁵═H,C₁-C₂₂-alkyl, C₂-C₂₂-alkenyl or C₆-C₁₀-aryl, and/or c) the salts of a)and b).
 4. The process of claim 1 wherein the polymer thermal stabilizermixture comprises at least a) a perchlorate salt and/or b) a reactionproduct of a mono- or polyfunctional epoxide and ammonia or,respectively, a mono- or polyfunctional dialkyl(aryl)- ormonoalkyl(aryl)amine and/or c) salts of a) and b).
 5. The process ofclaim 4, wherein the polyfunctional epoxide is dicyclopentadienedioxide, vinylcyclohexene diepoxide, bishpenol A diglycidyl ether ortrisglycidyl isocyanurate and the dialkylamine is diethanolamine ordiisopropanolamine and the monoalkylamine is monoethanolamine ormonoisopropanolamine.
 6. The process of claim 3 wherein the perchloratesalt is a compound of the formula M(ClO₄)_(n), where M is H, Li, Na, K,Mg, Ca, Sr, Ba, Zn, Al, La, Ce or NH₄ and n is either 1, 2 or 3 asrequired by the valency of M.
 7. The process of claim 3 wherein, in thecompound having the general formula (I), R³ _(a) and R³ _(b),independently of one another, are H or CH₃ and y=1.
 8. The process ofclaim 3 wherein, in the compound having the general formula (I),R¹═R²═CH₂—CHR₃—OH.
 9. The process of claim 6 wherein, in the perchloratesalt, M=Na or K and n=1.
 10. The process of claim 3 wherein thecompounds of the general formula (I) are selected from the groupconsisting of tris(2-hydroxy-1-propyl)amine, tris(2-hydroxy-ethyl)amine,bis(2-hydroxyethyl)-2-hydroxy-1-propylamine,alkyl/alkenylbis(2-hydroxyethyl)amine,alkyl/alkenyl(2-hydroxy-1-propyl)-amine,N-(2-hydroxyhexadecyl)diethanolamine,-2-hydroxy-3-octyloxypropyl)diethanolamine,N-(2-hydroxy-3-decyloxypropyl)diethanolamine, and mixtures of these. 11.The process of claim 3 wherein the polymer thermal stabilizer mixture iscomprised of from 0.01 to 3.00 parts by weight of sodium perchlorateand/or from 0 to 8.00 parts by weight of alkanolamines of the generalformula (I) and/or from 0.01 to 5.00 parts by weight of the salts of a)and b), per hundred parts of polymer.
 12. The process of claim 1 furthercomprising the step of subsequently stabilizing the polymer usingconventional stabilizers and/or additives.
 13. A composition comprisinga polymer that has been prepared by the process of claim
 1. 14. Aprocess for manufacturing useful articles comprising employinghalogen-containing polymers prepared according to claim
 1. 15. Anarticle of manufacture comprising a thermally stabilizedhalogen-containing polymer prepared by the process of claim 1.